It all revolves around the rather thorny concepts of 'Diplomatic Immunity' and 'National Reciprocity'. The State Department is constantly worried that another country will start taxing our diplomats and possessions if we don't play 'nice'.
My proposal and solution is to bid the Unrealistic Nations a happy farewell and let some deserving country host them, like North Korea or Iran. It will make for easier weapons inspection, right?
Article 1, Section 8:
The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;
If the Sec State can levy or forgive taxes, I can’t find it.
(not directed at you SES...just general frustration)